#Once you understand logic, you can apply the same principles to looping

languages = ["Python", "C++", "Java"]

for x in languages:

print(x)

#The body of this loop (the indented part) will run 4 times

#Each time is known as an iteration

#Each iteration, the variable x will contain one element

#iteration 1 will be the first element

#iteration 2 will be the next, and so on.

#The loop automatically stops.

#The variable name is irrelevant

for language in languages:

print(language)

########## PRINT WITHOUT NEWLINE ##########

print("One", end=" ")

print("Line")

#This is useful for loops where you don't want to spam the terminal

for language in languages:

print(language, end =" ")

print()

#can end with newline tfor future prints

#You could alternatively use end="\t" or end="" or whatever you want.

#You might be confused why we have to put end and not just:

print("DOEN'T AFFECT END", " ")

#Because this is interpretted as a second argument to print

#resulting in a printed " " followed by a newline.

#We must use end= (This is an example of keyword argument)

########## RANGE FUNCTION ##########

#instead of iterating through a list, we can use a function called range

#This loop runs 10 times

for i in range(10):

print("loading...", end= " ")

print()

#i is known as in iteration variable

#i will obtain a value each iteration based on the range we select.

#for range(10), we get 0-9:

for i in range(10):

print(i, end=" ")

print()

#Important: the value to end at is never part of the range.

#With range(10) we get 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

########## RANGE START POSITION ##########

#We can count 1-10 instead of 0-9 if desired:

for i in range (1, 11):

print(i, end=" ")

print()

#We can start anywhere and end anywhere

for i in range (5, 7):

print(i, end=" ")

print()

########## RANGE STEP ##########

#Go the other way.

#9 included. -1 not included (result is 9-0)

for i in range (9, -1, -1):

print(i, end=" ")

print()

#The third argument is called the step. we can set it to whatever

#Count down from 100 to 0, by 10s.

for i in range (100, -1, -10):

print(i, end=" ")

print()

########## SUM OF LIST ##########

#https://docs.python.org/3/library/math.html

#methods taking an iterable can take a range (sum, prod)

#Sum of numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

print(sum(range(1, 11)))

########## LIST FROM RANGE ##########

#We can make the range an official list using the list ctor

#https://docs.python.org/3/library/stdtypes.html#list

numbers = list(range(1, 11))

print(numbers)

#This is the besr way to easily print a list

#as print(range(1,11)) doesn't work as expected

########## FOR LOOP WITH INDEX ##########

languages = ["Python", "C++", "Java"]

for i in range(len(languages)):

print(i, languages[i])

#len will return 3. Passing 3 to range gives us 0, 1, 2